Zac Goldsmith’s loss to the Lib Dems in Richmond was one way in which a “Brexit byelection” can go. Tomorrow’s byelection in Sleaford represents the other side, where the smart money is on the Lincolnshire constituency reaffirming its referendum position of “listen to us, we want out”.

The “working class” crisis consuming politics is not simply an economic problem but a cultural one. All politics is identity politics, a way of communicating who we want to be, and who we don’t want to be. Embracing a romantic past can be seen as regressive, but nostalgia is a driver in these places because decades of modernity have left people without a sense of place and little in return for this dislocation.

It’s a feeling I recognise. The town I grew up in was built around the manufacture of munitions during the second world war. The Aycliffe Angels, the predominantly female workforce of Royal Ordnance Factory 59, manufactured 700m bullets for the war effort. I grew up thinking it unexceptional that I could visit the world’s first public steam railway line. Where I live now, we are still proud of Middlesbrough’s legacy of iron and steel working. “Ironopolis” produced the engineers that built the Sydney Harbour Bridge. Teesside steel “built the world”. Industrial history contributes to local identity.

As technology and global markets shifted, deindustrialisation changed the landscape. Margaret Thatcher’s revolution embraced that shift, deciding it was cheaper to pay people to be out of work than to keep industries afloat. Growth was unevenly distributed: aggregate GDP figures masked pockets of severe deprivation and real regional inequalities. Whole workforces were made obsolete, and successive governments failed to come up with strategies that would treat these people with dignity. Neither Tory paternalism nor Labour complacency addressed the growing disillusionment.

If your sense of self worth is tied up with work, realising that the people who profited from your blackened lungs see you as disposable creates a deep feeling of betrayal. The problem was not simply that coal and steel went elsewhere, but that the generations who’d sacrificed their health and lives to extractive and punishing industries were to be rewarded with unemployment, low wages and debt. More jarringly, they would be subject to disdain and dismissal. You can point a finger at university feminist societies if it makes you feel better, but it wasn’t earnest lefty students who consciously chose to avoid full employment policies and shouted at “scroungers” for needing income support to top up the 18-hour job in a call centre they had to fight with 400 other applicants to get.

Supposedly, those on the left have not focused enough on economic concerns because they’ve been obsessed with culture; but critics don’t offer any economic ideas. As always, the complex and multilayered identities of the working class are simplified, used to give middle-class nationalism a coat of authenticity, then tossed aside. We lament how people trapped in regions of long-term, structural deprivation vote out of frustration, but those on the left who did speak out against austerity and inequality were dismissed as unserious by the same people who now wring their hands.

Our current fashion of trying to separate out issues of “identity” from issues of economics is absurd. The traumas of marginalised communities are deeply tied up with economic deprivation. Discrimination makes people poorer, and poverty makes people more susceptible to exploitation. Women who are financially dependent on men find it harder to leave abusive relationships. People facing discrimination in employment and housing are more likely to be at the mercy of wage-stealing bosses and slumlords. Discrimination is not about hurt feelings, it is about real damage measurable in lost money and life-years. Believing that the economic needs of “working people” in the UK are somehow at odds with the economic marginalisation of minority populations only shows that those vacuously raging against “identity politics” lack the depth to engage with either economics or the long history of civil-rights activism.

If we want to engage with the concerns of the working class we need a proper analysis of the structural mistakes of the past 50 years. Capitalism runs on sales, but governments kept wages low in the name of “competitiveness” and relied on cheap debt to finance consumption. The household sector can no longer borrow its way to growth: we need to put actual money into their pockets, not just credit backed by inflated house prices, so that they can pay down their historically high debt burden and avoid triggering another cycle of debt deflation such as the one that crippled us in 2008.

We need to admit that the orthodoxies that led us here have failed, especially the lazy off-brand Hayekian thought that passes for an economic consensus. We should try listening to economists such as Ha-Joon Chang and Mariana Mazzucato and remember that economics is politics, with serious philosophical foundations that can, and must, be challenged. For too long we have believed there is one “right” set of economic policies and that any negatives are inevitable. This needs to be wholly discarded: we need to talk about the outcomes we want to see and choose our economic policies to get there.

Ask people on the ground in hollowed-out, leave-voting towns and they know, deep down, that a lot of their issues don’t really have anything to do with the EU, but they will say “it’s all part of the same thing”. Brexit is about reclaiming something lost. You have to recognise that, but you can’t pretend frustration is a policy.

The Tories hope repeating “Brexit means Brexit” will continue their successful run of avoiding alienating half the “leave” crowd by actually having to reveal which of the many Brexits they are going for. It’s the smart play. But what happens when they have to pay the piper later on is anyone’s guess. Once Brexit has been through the sausage factory of political compromise it’s hard to see this coalition of people with mutually incompatible fantasies holding together.

I expect that the political establishment will just about have worked out how to do politics in the post-Brexit environment by the time another political crisis pushes us into the post-post-Brexit era, and we’ll be subject to another round of discussing how it all went wrong, but we’ll all have failed the people of towns like Sleaford again.

Politics right now needs insight, not navel-gazing. How long is it going to be before we actually get some?

• You can catch up on the discussion on this article and others on our Your Opinions thread